cmake: fix static library checking
gles: plumb view matrices to all drawers
gles: plumb through a model matrix
gles: add a shader program helper class
screen: expose brightness
letter: port to opengles-compatible calls
WIP: screen: port to opengles-compatible calls
WIP: actor: add a close method to actors
WIP: starparticle: port to opengles-compatible calls
WIP: connectedparticle: port to opengles-compatible calls
WIP: field: port to opengles-compatible calls